Dimuon production in PbPb collisions at 20-160 AGeV at the CERN SPS: Mapping the QCD phase diagram in the transition region with a new NA60-like experiment

The structure of the QCD phase diagram for moderate temperatures and high baryon densities is still almost unexplored. Here, the QGP and hadronic phases should be separated by a first order transition region which is expected to end with a critical point. In this regime, dilepton measurements provide a rich set of observables to shed light on the onset of deconfinement and on the issue of chiral symmetry restoration. The objective of this paper is to present a proposal for a new NA60-like experiment (NA60+) to measure dimuon production with unprecedented precision in a comprehensive low energy scan at the CERN SPS. The CERN SPS is unique for systematic investigations along these lines, because this accelerator will be able to deliver high quality intense beams to perform systematic measurements of electromagnetic radiation over the full energy range from similar to 20 to 160 AGeV. (C) 2014 Elsevier B.V. All rights reserved.